In automotive applications, the Lane Departure Warning System (LDW) is a system included in the Smart Driving application or one of the Advanced Driver Assistance Systems (ADAS). It can help the driver to avoid accidents; in particular, it alerts the driver if the vehicle is inadvertently leaving the lane.
Today the ADAS applications are widely diffused due to the high sensibility in the automotive industry for the Safety Driving. The success of these applications is also due to the fact that a growing number of manufactures produce sensor chip really performing.
The LDW is a safety feature which lets the driver know if he is beginning to drift from lane either due to inattention or drowsiness.
Solutions are known to implement a LDW function.
European patent document EP 2477139 A2 discloses a method which provides extracting image edges from an image of the road acquired through a camera and emphasizing edge components by the histogram analysis stretching. Subsequently straight-line components are detected in the edge components the through the Hough transform.
U.S. Pat. No. 8,279,280 discloses that, in order to detect lane dividing lines, for example, an edge filter, a lane-dividing line highlight filter, etc. may be used. Preferably, the edge filter is suitably configured to detect a portion constituting a boundary in the image using a difference in the brightness values of respective pixels arranged in X and Y directions in an image coordinate system. The pitch angle between the road and the camera is calculated using the results of detection of the left and right lane-dividing lines, a vanishing point at which the left and right lane dividing lines suitably intersect, and a reference value required for the calculation of the lane width changes according to the location of the vanishing point.
U.S. Pat. No. 8,594,890 discloses a method for generating lane departure warning that include extracting from digital images the lane marking lines position based on the analysis of the image brightness changes. A couples of points where the brightness changes abruptly from dark to bright and a couple of points where the brightness changes abruptly from bright to dark are identified in the image. The marking lines can be detected by finding a combination of such points. The marking lines position is used for estimating the probability of lane departure calculating the position of parts of the vehicle using other information such as information on the steering, such as the yaw rate and the lateral acceleration.
The drawback of the technique is that requires taking in account inputs from different sensors besides the camera and parameters which are vehicle-specific.